Fix reflection of constraints in attached schemas
Backported a fix for SQLite reflection of unique constraints in attached
schemas, released in 2.0 as a small part of :ticket:`4379`. Previously,
unique constraints in attached schemas would be ignored by SQLite
reflection. Pull request courtesy Michael Gorven.
Fixes: #8866
Closes: #8867
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/8867
Pull-request-sha:
94a5736170f5c944d3dad1ef91dc8550c72a4dc5
Change-Id: Id414aeed9d6ce58877d81df2459f6d4f308750a8